紫膜碎片的电二色性研究

ELECTRICALLY LINEAR DICHROISM STLDEES OF PURPLE MEMBRANE FRAGMENTS

悬浮在水中的嗜盐菌紫膜碎片,在外电场作用下产主定向排列.在20℃时,568nm的电二色性研究表明:外加电场为2kV/m时取向程度可达60%以上;大于5.5kV/m时,取向作用趋于饱和状态;饱和时简约电二色性为-0.437左右,视黄醛生色团的跃迁矩方向与电偶极矩方向形成60.9°夹角;紫膜的永久偶极短为9.2×10^(-24)C、M,剩余电极化率为3.0×10^(-27)m^2;紫膜的旋转扩散常数为0.53秒^(-1).曲线拟合分析表明,感应偶极对紫膜碎片的定向的贡献应予考虑.本文对紫膜碎片的定向机理进行了讨论.

Purple membrane (PM) fragments from Halobacterium halobium R1M1 were oriented by a static electric field in a water suspension. It was found by electrically linear dichroism at 20 C that the orientation degree is up to 60% when an electric field of 2kV/m is applied, and the orientation is tend to saturation when the field is more than 5.5kV/m; that the PM has a permanent electric dipole moment of 9.2 × 10-24C. m, and their electrically excess polarizablity of 3.0 × 10-27F. m2, the orientation of the retinal transition moment relative to the direction of the electric dipole moment is 60.9°, and the PM rotational diffusion constant D=0.53S-1.The curve fitting analysis showed that, the contribution of the induced electric dipole to the orientation of the PM fragments should be considered.